shellRadius
plain-language theorem explainer
shellRadius defines the radius of the k-th solvation shell as phi raised to the power k. Chemists modeling the five canonical hydration layers around an ionic solute in water cite this when the adjacent-shell ratio must equal phi. The definition is a direct one-line power assignment in the reals.
Claim. The radius of the k-th solvation shell is defined by $r_k = phi^k$, where $phi$ is the golden ratio fixed point of the Recognition Composition Law.
background
The module treats five canonical solvation shells for an ionic solute in water when configDim equals 5: primary hydration, secondary hydration, tertiary hydration, bulk-boundary layer, and far bulk. Shell radii sit on the phi-ladder so that the ratio between adjacent shells is exactly phi. This definition supplies the explicit radii required by downstream results such as shellRadius_ratio and SolvationShellCert.
proof idea
One-line definition that directly assigns shellRadius k to phi raised to the power k.
why it matters
This definition supplies the explicit phi-ladder radii for the five solvation shells required by SolvationShellCert. It is used by shellRadius_ratio to prove the adjacent ratio equals phi and by shellRadius_pos to establish positivity. The construction realizes the phi-ladder at B10 Chemistry Depth, consistent with the self-similar fixed point T6 and the eight-tick octave in the forcing chain.
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